1. Technical Field
The present invention relates to a nestable chair.
2. Related Art
In order to save a storage space when a chair is not in use, an operation of fitting (nesting) chairs each other in a front-rear direction (a horizontal direction) has been widely performed. As a nestable chair, a type referred to as a pipe chair in which a body frame is configured by a metallic pipe has been used in many cases. Also, a chair (a swivel chair) in which an extendable gas cylinder is used for a leg and which is made to be nestable has been suggested. An example thereof is disclosed in Patent Documents 1 and 2.
Specifically, according to Patent Document 1, legs are configured as four front and rear branched legs, a height of the two front branched legs is set to be lower than a height of the two rear branched legs and an extended angle of the two front branched legs is set to be less than an extended angle of the two rear branched legs, so that support devices arranged at the front and the rear can be fitted with each other.
A backrest is attached to a fixed base oblong in a left-right direction and provided on an upper end of a leg column (the gas cylinder) through left and right back frames, and a resistance against the rocking of the backrest is provided by a torsion bar embedded in the fixed base. A lower surface of a seat is formed at a substantial center part in the front-rear direction with bearing brackets protruding downwardly and configured to be rotatably fitted to spindle parts provided for the fixed base, so that the seat is permitted to be raised and rotated. Therefore, a raising and rotating center of the seat and a tilting center (a rotating center) of the backrest are concentric.
According to Patent Document 1, since the intermediate part of the seat in the front-rear direction is coupled to the fixed base, a lower half part of the seat is positioned below a lower end of the back and the fixed base at a raised state. Also, an empty space for permitting a rear half part of the seat to be rotated downwardly is provided at the rear of the fixed base.
While the seat can be horizontally rotated relative to the support device, the support device has directionality upon the nesting. Thus, Patent Document 1 discloses that when the seat is raised, the support device is positioned at a nestable posture. Also, when the seat is raised, a locked state of the gas cylinder is released, so that the seat is raised to the highest position. Thereby, it is possible to secure the deepest fitting and to align the heights of the respective chairs at the nesting state to thus have a favorable appearance.
According to Patent Document 2, a seat has a circular shape, as seen from above, is provided with an armrest and backrest part extending half around a rear side of the seat, as seen from above, and is coupled at an intermediate part thereof in the front-rear direction to a fixed base through a link. When the armrest and backrest part is tilted forwards, the seat is rotated to a back inclined posture.